"Characteristics Associated With Differences in Survival Among Black and White Women With Breast Cancer" 
JAMA Jul 2013
http://jama.jamanetwork.com/article.aspx?articleid=1719739 
"Conclusions and Relevance  In the SEER-Medicare database, differences in breast cancer survival between black and white women did not substantially change among women diagnosed between 1991 and 2005. These differences in survival appear primarily related to presentation characteristics at diagnosis rather than treatment differences."